Scientist calculates the 'sad, lonely' end of the universe

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'It's like saying the word 'trillion' almost a hundred times.'

This visualization depicts a dark brown dwarf, which might resemble a black dwarf.  (Image credit: NASA/JPL-Caltech)

Stars will continue to explode long after the universe is cold and "dead," one scientist determined in diving down the rabbit hole to find the last supernova that will ever happen.

When the universe as we know it "dies," it will be "a bit of a sad, lonely, cold place," theoretical physicist Matt Caplan, an assistant professor of physics at Illinois State University, said in a statement. In a new study, Caplan calculated how dead stars might change over time and determined when the last supernova will explode in the universe's distant future. 

The universe's end is "known as 'heat death,' where the universe will be mostly black holes and burned-out stars," Caplan explained in the statement. "I became a physicist for one reason. I wanted to think about the big questions — why is the universe here, and how will it end?" 

Related: Supernova Photos: Great Images of Star Explosions

It's like saying the word 'trillion' almost a hundred times.

— theoretical physicist Matt Caplan

In the new study, Caplan looked to the future of stellar explosions. Massive stars explode in supernovas when iron builds up in their core, accumulating and triggering the star's collapse. But smaller stars such as white dwarfs — ultradense stellar corpses that form when sunlike stars exhaust all of their nuclear fuel — don't have the gravity and density to produce this iron. However, Caplan found that, over time, white dwarfs might become denser and become "black dwarf" stars that can actually produce iron. 

"As white dwarfs cool down over the next few trillion years, they’ll grow dimmer, eventually freeze solid, and become ‘black dwarf’ stars that no longer shine," Caplan said. “Stars shine because of thermonuclear fusion — they’re hot enough to smash small nuclei together to make larger nuclei, which releases energy. White dwarfs are ash, they’re burnt out, but fusion reactions can still happen because of quantum tunneling, only much slower." 

Quantum tunneling is a phenomenon in which a subatomic particle "tunnels" through a barrier that seems impossible to penetrate when it disappears reappears on the other side of the barrier.

Caplan noted that this fusion is key for creating iron within black dwarfs and triggering this type of supernova. 

The new study shows how much iron black dwarfs of different sizes would need to create in order to explode. Caplan calculated that the first of these "black dwarf supernovas" will explode in about 10 to the 1,1000th years — an almost inconceivably large number. "In years, it’s like saying the word ‘trillion’ almost a hundred times. If you wrote it out, it would take up most of a page. It’s mindbogglingly far in the future," he said.

He found that the most massive black dwarfs will explode first, followed by less and less massive stars until there are none left, which he expects will be in about 10^3,2000 years. "It’s hard to imagine anything coming after that," he said. "Black dwarf supernova might be the last interesting thing to happen in the universe. They may be the last supernova ever." 

So what will the "sad, lonely" universe be like at this point, after the last supernova has exploded? According to Caplan, "Galaxies will have dispersed, black holes will have evaporated, and the expansion of the universe will have pulled all remaining objects so far apart that none will ever see any of the others explode. It won’t even be physically possible for light to travel that far."

This study was published Aug. 7 in the journal Monthly Notices of the Royal Astronomical Society. 

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Chelsea Gohd
Chelsea Gohd
Senior Writer

Chelsea “Foxanne” Gohd joined Space.com in 2018 and is now a Senior Writer, writing about everything from climate change to planetary science and human spaceflight in both articles and on-camera in videos. With a degree in Public Health and biological sciences, Chelsea has written and worked for institutions including the American Museum of Natural History, Scientific American, Discover Magazine Blog, Astronomy Magazine and Live Science. When not writing, editing or filming something space-y, Chelsea "Foxanne" Gohd is writing music and performing as Foxanne, even launching a song to space in 2021 with Inspiration4. You can follow her on Twitter @chelsea_gohd and @foxannemusic.

68 Comments Comment from the forums
  • Fourth Root
    Twice in the article you placed commas in confusing and incorrect positions in the numbers.
    Once at "will explode in about 10 to the 1,1000th years "
    Another at "which he expects will be in about 10^3,2000 years."

    Those numbers are now ambiguous and meaningless. How could this same obvious error be made twice?
    Reply
  • rod
    FYI, you can read the correct exponents on this white dwarf calculation here, https://forums.space.com/threads/cyclical-universe.32431/page-9#post-523217 The NASA ADS Abstract and arXiv report is at, The NASA ADS Abstract, 'Black Dwarf Supernova in the Far Future', https://ui.adsabs.harvard.edu/abs/2020MNRAS.tmp.2391C/abstract, August 2020.

    It is 10^1100 and 10^32000 years. The white dwarfs slowly evolve into black dwarfs as the universe expands and ages. This new, stellar evolution model follows the 2nd Law and contradicts cyclic universe beliefs or eternal inflating universe beliefs. The white dwarf population documented in astronomy today shows the universe is finite in age and had a distinct beginning that is winding down, not up. White dwarfs will age and become black dwarfs, some will blow up too in the end, the universe dies heat death :)
    Reply
  • dfjchem721
    Well there certainly aren't many presumptions made in these calculations. :)

    They say he went down "the rabbit hole", and in this case appears to be truly reporting from "Wonderland" rather than a reality-based position. It sure makes some people wonder about the "science" of such prognostications.

    Going down the rabbit hole is usually defined as "To enter into a situation or begin a process or journey that is particularly strange, problematic, difficult, complex, or chaotic, especially one that becomes increasingly so as it develops or unfolds." (stolen from google search). Somehow this basic concept does not lend a great deal of credibility for some of us.

    All joking aside now, for some the one thing that really lit up the screen was:

    "Caplan explained in the statement. "I became a physicist for one reason. I wanted to think about the big questions — why is the universe here, and how will it end?"

    For those of us who deny divine interventions, there is no "why" in science, there is only "how". They are vastly different questions in the scientific arena. Again, there is NO "why", at least for those grounded in fact-based observations and considerations.

    Many would bet big money, and giving long odds, that more than a few will quibble with Caplan's "rabbit hole calculations."
    Reply
  • Torbjorn Larsson
    Cool result - literary!

    Earlier it was the super massive black holes that were believed to go last into the heat death of the current cosmology. Oh well, an exotic object and a couple of orders of magnitudes - potato, potatoe.

    dfjchem721 said:
    Well there certainly aren't many presumptions made in these calculations. :)

    They say he went down "the rabbit hole", and in this case appears to be truly reporting from "Wonderland" rather than a reality-based position. It sure makes some people wonder about the "science" of such prognostications.

    Going down the rabbit hole is usually defined as "To enter into a situation or begin a process or journey that is particularly strange, problematic, difficult, complex, or chaotic, especially one that becomes increasingly so as it develops or unfolds." (stolen from google search). Somehow this basic concept does not lend a great deal of credibility for some of us.

    All joking aside now, for some the one thing that really lit up the screen was:

    "Caplan explained in the statement. "I became a physicist for one reason. I wanted to think about the big questions — why is the universe here, and how will it end?"

    For those of us who deny divine interventions, there is no "why" in science, there is only "how". They are vastly different questions in the scientific arena. Again, there is NO "why", at least for those grounded in fact-based observations and considerations.

    Many would bet big money, and giving long odds, that more than a few will quibble with Caplan's "rabbit hole calculations."

    If the first part of the post is the joke, let me just nitpick and note that the work is the reality-based position - a first order estimate from known physics. The non-joke question would be if it is testable. Who knows (maybe it's in the paper, but the topic is rather obscure).

    More non-joke spurred from your comment, in general an empirical position cannot "deny" anything without being given reason to - anything can happen. But I think we now know religion is as rejected by observation as astrology is - large scale work or work results are impossible in a flat space universe (no net work went into it or any of its sufficiently large sub volumes - it's all spontaneous phase transitions). Added to earlier discoveries that religious magic rituals or thinking doesn't work ("intercessory prayer" doesn't work, LHC tells us there isn't enough exotic processes left for 'souls' or 'afterlife' in the biochemical machines that are us) and that's at least the same level of evidence that rejected astrology in the 80's (with blind studies and much older astronomical/light speed physics results). Arguably more since both cosmology and perturbation theory (Feynman diagrams) of the quantum vacuum are watertight, both capture net work or low energy 'something else' and wouldn't work out the way they do if such exist.
    Reply
  • Helio
    If quantum tunneling can produce iron over eons of time, why wouldn't the same process do the same to split iron apart, thus never allowing a black dwarf to explode?
    Reply
  • Spaceman Spiff
    dfjchem721 said:
    Well there certainly aren't many presumptions made in these calculations. :)

    They say he went down "the rabbit hole", and in this case appears to be truly reporting from "Wonderland" rather than a reality-based position. It sure makes some people wonder about the "science" of such prognostications.

    Going down the rabbit hole is usually defined as "To enter into a situation or begin a process or journey that is particularly strange, problematic, difficult, complex, or chaotic, especially one that becomes increasingly so as it develops or unfolds." (stolen from google search). Somehow this basic concept does not lend a great deal of credibility for some of us.

    All joking aside now, for some the one thing that really lit up the screen was:

    "Caplan explained in the statement. "I became a physicist for one reason. I wanted to think about the big questions — why is the universe here, and how will it end?"

    For those of us who deny divine interventions, there is no "why" in science, there is only "how". They are vastly different questions in the scientific arena. Again, there is NO "why", at least for those grounded in fact-based observations and considerations.

    Many would bet big money, and giving long odds, that more than a few will quibble with Caplan's "rabbit hole calculations."
    On what evidence do you deny divine, or otherwise unknown or unknowable intervention? After long investigation, the "how" may in fact turn out to be a "why". What the likelihood of that is we can't say, but we can't state with absolute certainty that there is NO "why".
    Reply
  • Helio
    The "how" is what science seeks. The "why" will always be subjective and outside the purview of science.

    If we go back to the 17th century and beyond, both were combined, though science was in its pre-modern era. Purpose was seen in most scientific discoveries. Divine purpose and efficacy were seemingly apparent. It helped spur interest in science and in forming universities. Paley's Natural Theology (~ 1800) was extremely popular and beloved by Darwin.

    The term used for purposeful science is teleology.

    Today, however, philosophy and religion are often regarded as NOMA (non-overlapping magisteria, per Gould), though sometimes there are some overlaps.
    Reply
  • dfjchem721
    Spaceman Spiff said:
    On what evidence do you deny divine, or otherwise unknown or unknowable intervention?

    Some might use your question as the answer. It all boils down to the "unknowable" aspect, which has no meaning for many. This is all purely "philosophical" in nature and does not intrude on the realm of fact-based science.

    Science discovers things and make them work without consideration of unknowable interventions, and related concepts. That does not mean that people who ask "why?" are wrong to do so, only that science has no answer for them.
    Reply
  • Atlan0001
    If the premise is wrong then the structure built over it will be as a house that is built upon shifting sands.

    The Universe (a.k.a. a multi-dimensional Multiverse) isn't even close to being on its way to a long sad lonely end. It is an infinite of mass for one thing, a still existing Big Crunch. A constant. That infinite of mass is a binary constant, at once infinitesimal in mass. A Big Hole, also constant of course (binary). That infinite of mass, that Big Crunch/Big Hole did not go away. It does not go away. It will not go away. The 'vacuum of space' does not and will not go into any long sad lonely end. Nor does the 'vacuum energy', the many, many, vacuum energies, including the matter, of the macro-verse. Nor do the many, many, vacuums of the micro-verse and quantum mechanics. That binary, that infinite of mass/that infinitesimal of mass, is fully present everywhere and at all times in the finite universes, the Universe's infinity of finite universes divided by horizons only into boundary-less finites. You might go to a long sad lonely end eventually. The planet Earth will eventually. Stars will come and go as vacuum energies do. Galaxies will come and go, as vacuum energies do. But universes and the Universe (a.k.a. a multi-dimensional Multiverse) won't, The base won't; the binary Big Crunch/Big Hole (the binary infinite of mass/infinitesimal of mass) won't. Infinity doesn't gain or lose anything. It may seem to in small, local, detail, in fine structure, but in the infinite/infinitesimal, and across the infinity of finites, it doesn't gain or lose a thing.
    Reply
  • rod
    FYI. In post #3, the NASA ADS Abstract has the arXiv paper. Here is an important statement in it. From the NASA ADS Abstract, arXiv paper "9 CONCLUSIONS Black dwarf supernova progenitors with masses between about 1.16 and 1.35 M⊙ are at near zero temperature which allows us to determine their internal structure with fair accuracy using only a relativistic Fermi gas. Furthermore we can calculate their lifetimes with simple analytical formulas for the pycnonuclear reaction rates at the surfaces of their iron cores. If proton decay does not occur then in the far future we expect approximately one percent of all stars today, about 10^21 stars, to collapse and explode in supernova beginning in approximately 10^1100 years and lasting no more than
    about 10^32000 years. At such advanced time it is difficult to imagine any other astrophysical processes occurring, which may make black dwarf supernova the last transients to occur in our universe prior to
    heat death..."

    The white dwarfs on the H-R diagram are indeed evidence of a universe with distinct beginning and much younger age than stellar evolution showing the arrival of black dwarfs. The white dwarfs, and now the calculations for black dwarfs - support a universe that is not cyclical. It is moving towards heat death as this new paper shows. A distinct beginning of the universe and white dwarfs future is shown here. Difficult for the eternal universe folks to accept :)
    Reply